Improvement in mechanical telephones



UNITED STATES PATENT OEEIcE.

JOSEPH TW. MAXVELL, 0F LOISVLLE, KENTUCKY.

lMPROVEMENT lN MECHANICAL TELEPHQNES.

Speeilieation forming part of Letters Patent NO. 216,051, dated June Zi, i579, application filed November 7, 1578. a

To all Iwhom 'it 'may concern:

lie it known that i, JosErii W. MaxwELL, ot' the citv of Louisville, county ot' J cii'erson, and State ot Kentucky, have invented certain Improvements in Telephony, oi which the ollowing is a speciiication.

Vhereas in an application made by myself for Letters i atent of the United States, iiled in the United States Patent Oiliec en the 14th day ot October, i378, for in'iprovementin telephony, I have shown and described an apparatus (among other things) consisting of two sounding-boards and their vibrators, ot' the same construction and material, placed together apex to apex, aoart a iiew inches only, on the same transmitting-wirc, and connected together by another short wire, which extends i'rom the apex of one to the apex ot' the other, the means or' fastening` being knots iorined on the extremities of the short wire after they had been extended tlni'eugh the vibrators; one appara tus consisting ot' this combination of parts is placed at each end et' a lon transmitting-wire, which is passed through the centers ot' the vibrators, and over and along which vibrations oi' air or sounds are transmitted from one end ot' the line to the other, and each apparatus is held 'to its connection with the wire by a button on each, end thereo'i", and the wire is held taut or otherwise, as the one apparatus may be moved to or from the other.

The soinnling-boards may be made et' sett pine wood, or any other suitable material, and should have openings in their central portions, over which the vibrators are to be fastened, and should be mounted upon suitable supports or inelosed in suitable boxes, and should be made quite thin, in order to increase their ca paeity for vibration; and the vibrators are made oi' sheep skin or like material, and should be fastened upon the sounding-hearts over the ogenin gs therein while in. a wet and plastic condition, and then have their central portions drawn ont and stretched until they assume a funnel-like forni, and then be allowed to dry and retain that forni.

New niy invention herein claimed relates to 'the construct-ion of a vibratory apparatus of quite diderent form and of a much betterre suit from the one"hereinbefore described.

It consists, to seine extent, of an inclosing box, within which the vibrators are operated, the box having a suitable opening in and through the end or' it which is opposite to the other end of the line of eonnnunication, inte which vibrations are received and ont of which they are delivered, but the apparatus proper consists ot' two diaphragms or vibrators ot' the saine material before mentioned, and one of them et exactly the same forni, and the other ot' the same general form, but having a central opening init, to correspond in iorin and size with the one in the end of the containingbox before mentioned; and these two vibrators, which are in a circular forni, by their outer edges are fastened to and upon the two opposite sides of a thin board of soft pine wood, or other vibratory wood or material, with their concave sides next to each other, and the board is cut away in the center, so as to leave a large opening in circular form in it, and the residue ot' the board serves as a frame for the two vibrators to hold their outer edges distcnded, and it does not touch the containn ing-box at all 5 and the one of the vibrators having the opening' in it has the edge around the opening 'fastened upon another board, which has also anopening in it, corresponding in size and forni with the one in the vibrator and the one in the end ofthe containing-box, and the board is attached to the inside oi' the end oi? the box, so that the openings in the vi brator, board, and box constitute an avenue for the reception and delivery of air-vibrations into and ont otl the apparatus. The transmit tin g-wire is passed in through the opposite end ofthe box, and through the apex of the vibra tor that has no central opening in it, and is there held by a button on the end oi' it on the.

inside or' the vibrator, and when the wire is stretched taut both vibrators are stretched and held tant likewise, and the whole appa-y ratus is held suspended upon the wire at one apex, and the attachment to the board (which is attached to the end of the box) at the other, and the-result of this construction is a high degree of vibratory powerb My said invention will be more particularly described with reference to the accompanying drawings, in which Figure l represents a central vertical longitudinal section oi' the said appa ratns described in my said application iiled October 22, 1878 and Fig. 2, a like View of the containing-box and operative parts of this my improvement claimed herein.

In Fig. 2, a indicates the board to which the outer edges of the vibrators are fastened; h, the vibrator, attached to the transmitting-wire T by the button e and h',- the other one of said Vibrators, and the same which has the central opening, n, in it; and k, the board to which that vibrator is attached .by the edge around its opening, and it is fastened upon the inside of the end of the box, so that the opening at u is through vibrator, board, and box. g indicates the cotton or lWool placed around the vibrators Within the box, in order to destroy the ring of the wire T. The vibrators are stretched and held taut by means of the button e on the Wire T; and but for the button t' on the Wire outside of the box the vibrators would collapse when the Wire was relaxed.

In this construction it will be observed that a large portion of the apparatus is 'made of the sheep-skin or other ani-mal membrane, and there is in it no more of Wood, which is itself capable of a high degree of vibration, than enough for a frame to hold the vibrators in position and proper shape, and that it is therefore very eicient for the purpose of condensing and strengthening air-vibrations for transmission, and I have found it to be so by actual experiment, much more so than the one shown in Fig. 1. l

I have found also by experiment that a vibrator that is from seven to eight inches in diameter through the center from one outeredge to the other is the most ejjicient, and that when they are much smallethan this the vibrations made by the vocal organs are of a nasal character; but Whenan apparatus of proper size is used at one end f the line, then a much smaller one may be used at the other without impairing perceptibly theeifect.

A very good effect is secured by using the construction shown in Fig. 2 at one endiof the line, and that shown in Fig. 1 at the ot er.

What I claim as my invention, and desire to secure by Letters Patent, is-

The vibratory apparatus composed of the vibrator h and the vibrator h', having the opening n, and the suspended board t and the xed board k', constructed and arranged sub# stantially as and for the purpose described.

J. W. MAXWELL.

Witnesses:

I. M. STEPHENs, A. M. SroUT. 

